Xbox Power Trace Repair
A problem often encountered in early versions (v1.0 and v1.1) of the original Xbox is that the trace which carries the power-on signal from the power button to the PIC chip becomes corroded, breaking the trace. Other nearby traces may also be affected, such as the eject button and the front panel LED, but usually the power trace is first affected. If the problem is caught early, you may be able to scrape the corrosion off of the trace, but if the trace has been completely severed, you will need to solder in a bypass wire.
You will need the following tools to complete this repair:
- A T20 torx screwdriver (to open the case)
- A T10 torx screwdriver (to remove the motherboard)
- A soldering iron. Flux is recommended.
- Hot glue gun (recommended for securing the solder joints)
- Electrical tape (recommended for securing the wire, any non-conductive tape will do)
Symptoms associated with a broken power trace include
- The Xbox powers on as soon as the AC power cable is inserted.
- The power button does not work, either to turn the system on or to turn it off.
- The Xbox will turn itself off randomly during gameplay.
- If you do manage to turn the Xbox off with the AC power still connected (which can be done through software such as EvoX or waiting for a random shutdown), the Xbox will eventually turn itself back on.
The first symptom you may experience, at least in my case, is that your Xbox will randomly turn itself on. If you see this happen and then go to turn the console off, but the power button is unresponsive, then most likely corrosion has just eaten through the power trace, and you should act quickly before the situation worsens.
The way the Xbox power and eject buttons work is simple to understand using the schematic to the side. When the button is not being pressed, the pin on the PIC chip (which receives the power and eject signals) is HIGH (V = Vcc). When the button is pressed, the PIC pin is connected to ground causing the signal on the pin to become LOW, and the Xbox powers on. The trace which can become corroded does not run directly from the switch to the PIC chip, but rather from the signal resistor to the PIC chip. By looking at the schematic, you can see that if that trace is broken, neither Vcc nor ground can connect to the pin, and so its state is left 'floating'. This is what causes the Xbox to power on and off randomly.
What causes the trace to become corroded is unclear, although it is generally believed to be a manufacturing defect which left contaminants on the board. The corrosion seems to start from the edges of the motherboard and work its way inward, which is why the power trace, the outermost trace on the board, is affected first. If the corrosion is allowed to spread, the eject button and LEDs will later begin to malfunction. There are currently no known cases of the corrosion occurring on the interior of the board.
To fix this problem, you must bypass the trace. There are two ways to go about this: the safer but more difficult way is to recreate the proper schematic for the power switch, which will require you to solder directly to the signal resistor, which is surface-mounted and thus easy to damage. It's also located on the top of the board, whereas the test point you solder to for the connection to the PIC chip is on the bottom. However, there is an easier way: simply bypass the signal resistor. You can solder directly to the socket that the front panel plugs into on the motherboard, which is much easier to do. I bypassed the signal resistor when repairing my Xbox and have not had a single issue, so the resistor does not appear to be necessary. It probably exists to prevent fluke power surges. This guide will explain how to do the repair by bypassing the resistor; if you wish to keep the signal resistor in the circuit, see the guide in the helpful links section.
- http://fillwithcoolblogname.blogspot.com/2011/02/1st-gen-xbox-trace-corrosion-repair.html - This is the guide that this article is based on.